I tried uninstalling and reinstalling the game from the itch.io app, and redoing the steps above with NWJS 0.51.2 and then with the SDK version of 0.52 - same result unfortunately.
I wonder what's different about our setups besides the base OS? Manjaro is rolling release so I'm running GNOME 3.38.4, Nvidia binary drivers 460.56, kernel 5.11.2.